Conspiracy theorist and UFO phenomenologist, Max Spiers was found dead in Warsaw, Poland over the summer and his death is cause for suspicion within the network of UFO researchers.

According to SF Gate, Spiers, 39, who is originally from England, texted his mother just days before he died. The message read, “If anything happens to me, investigate.”

Polish authorities indicated that Spiers’ death was due to natural causes, though his death has stoked conspiracy theories. His family says he was in perfect health, while some have speculated that he was poisoned.

According to Craig Hewlett, a UFO blogger, Spiers’ untimely death raises suspicions that he was likely on to something. Hewlett noted, “If it wasn’t true what he talks about then why would they kill him? Healthy people don’t just get sick and die, they get poisoned.”

Spiers’ mother, Vanessa Bates, told the Telegraph, “He was making a name for himself in the world of conspiracy theorists and had been invited to speak at a conference in Poland in July.”

She added, “But I think Max had been digging in some dark places and I fear that somebody wanted him dead.”

Bates said, “All I have is a death certificate from the Polish authorities that it was from natural causes, but no post-mortem was done so how can they tell that? They are also refusing to release any paperwork about it to me because, absurdly, I don’t have his written permission.”

While Bates has vowed to get to the bottom of what happened to her son, British UFO expert Nick Pope alleges that the conspiracy theories are just that. He took to Twitter to express his condolences over Spiers’ death, writing, “The death of Max Spiers was a tragedy, but having run the UK government’s UFO project I promise we don’t go around killing UFO researchers.”

The death of Max Spiers was a tragedy, but having run the UK government’s UFO project I promise we don’t go around killing UFO researchers.